Discharger shoe apparatus for centrifugal separator



July 24, 1956 THOLL ETAL 2,755,991

DISCHARGER SHOE APPARATUS FOR CENTRIFUGAL SEPARATOR Filed Aug. 8. 1952 5Sheets-Sheet l July 24, 1956 J. F. THOLL ETAL DISCHARGER SHOE APPARATUSFGR CENTRIFUGAL SEPARATOR Filed Aug. 8, 1952 5 Sheets-Sheet 2 July 24,1956 J. F. THOLL ErAL 2,755,991

DISCHARGER SHOE APPARATUS FOR CENTRIFUGAL SEPARATOR Filed Aug. 8, 1952 5Sheets-Sheet 3 July 24, 1956 J. F. THOLL ETAL 2,755,991

DISCHARGER SHOE APPARATUS FOR CENTRIFUGAL SEPARATOR Filed Aug. 8, 1952 5Sheets-Sheet 4 July 24, 1956 J. F. THOLL ETAL DISCHARGER SHOE APPARATUSFOR CENTRIFUGAL SEPARATOR Filed Aug. 8, 1952 5 Sheets-Sheet 5 W m, w a aQ Q m a m Q w 57% I AM 7 i 1 u .u n

g a a l'avea'afoaw flfiowraqy United States Patent DlS CI-IARGER SHOEAPPARATUS FUR CENTRIFUGAL SEPARATOR 1 John F. Tholl and David M. Tholl,Needham, Mass, assignors to American Tool 8; Machine Company, Enston,Mass, a corporation of Massachusetts Application August 8, 1952, SerialNo. 303,303

6 Claims. (Cl. 23310) This invention relates to an improved dischargershoe apparatus for use with centrifugal separators, and particularlywith centrifugal separators of the class having a stationary outercasing or curb formed with an opening at the upper side thereof, whichopening furnishes access to a rotatable basket received within the curb.

In devices of this general class heretofore proposed, it has beencustomary to utilize a manually operated positioning mechanism forswinging a shoe or scraper blade, commonly referred to as a dischargershoe element, inwardly in to a position of register with the curbopening, and then to raise or lower the shoe element in the basket inorder to remove material which may be hardened or caked on the innerwall surfaces of the basket. Necessarily the operator, in order to carryout such an operation, is required to stand in close proximity to theseparator mechanism, and since there is a very considerable danger ofinjury from the rapidly rotating basket, it has been the custom to stopthe operation of the machine while making the manual adjustments of thecontrol mechanism. This involved a loss of time and a generally lessefficient operation. Moreover, as such stopping and starting may occurfrequently, a very considerable torque stress problem develops in therotary driving mechanism, and it is in many cases found to be necessaryto provide in the rotary driving mechanism special torque arresting orcushioning devices adding measurably to the cost and bulk of themachine.

It is an object of the present invention to deal with these problems andto devise a discharger shoe apparatus for a centrifugal separator,including a control mechanism which operates automatically, with theresult that having once been placed in motion, the discharger shoe maybe positioned, as desired, at any time, while the centrifugal separatoris running and without stopping this member. It is a further object ofthe invention to provide a control mechanism which, owing to itsautomatic operation, makes it possible to avoid or eliminate the use ofexpensive torque arrestors.

These and other objects and novel features will be more fully understoodand appreciated from the following description of a preferred embodimentof the invention selected for purposes of illustration and shown in theaccompanying drawings, in which Fig. 1 is a plan view taken on the line1-1 of Fig. 2;

Fig. 2 is a side elevational view of the discharger shoe apparatus ofthe invention shown in one position of adjustment in association with atypical centrifugal separator of the class which includes a curb and arotatable basket mounted within the curb;

Fig. 3 is a fragmentary vertical cross-sectional view of the structureshown in Fig. 2, and further illustrating the discharger shoe mechanismin another position of adjustment in which the discharger shoe elementoccurs within the basket;

Fig. 4 is a fragmentary plan cross-sectional. view taken on the line 44of Fig. 3; 1

Fig. 5 is another plan cross-sectional view generally corresponding toFig. 4 but showing a modified form of discharger shoe blade or element;

Fig. 6 is a detail cross-sectional view of the actuating means for onepart of the discharger shoe mechanism;

Fig. 7 is an enlarged fragmentray plan cross-sectional view of portionsof the discharger shoe apparatus taken on the line 77 of Fig. 3;

Fig. 8 is an enlarged vertical cross-sectional view of discharger shoeholder means and actuating means therefor, these parts being shown asaunit removed from the supporting structure indicated in Figs. 1 and 2;

Fig. 9 is a vertical cross-sectional view taken on the line 9-9 of Fig.4; and

Fig. 10 is a perspective view showing the supporting base structure ofthe discharger shoe apparatus, including bearing portions and guidemeans from which parts of the shoe holder means shown in Fig. 8 havebeen removed.

In the structure shown in the drawings we have illustrated a typicalcentrifugal separator arrangement including vertical frame pieces, as 2and 4, which are carried on bottom members 3 and 5, as suggested inFigs. 1 and 2. Solidly secured to upper portions of the vertical framepieces 2 and 4 are transverse beams 6 and 8 which may, in turn, receivesuspension beams 10.

The above described construction comprises a rigid frame work which isnecessary to support a suspended driving motor 11 which, in turn,rotates a shaft 13 about a long vertical axis. As the length of thisvertical axis must be kept. as small as possible, the height of theenclosure defined by the frame work described has definite limitationsin order for the structure to properly support and rotate a basket 20suspended at the bottom of the shaft 13 (Fig; 2). This basket isenclosed in the usual manner within a casingor curb 16 which is formedin its upper side with an opening 18 furnishing access to the basket 20.The curb may, for example, be supported on brackets 12 and 14, as shownin Fig. 2.

As an aid to more fully understanding and appreciating the dischargershoe apparatus of the invention, it is pointed out that basket sizes anddepths may vary considerably. Thus, for many purposes, it may be foundto be most efficient to provide for basket depths running up to as. muchas thirty inches for a given diameter size, and in some cases thisdimension may be increased. It will be apparent that the depth of thebasket dictates, to a considerable extent, the length of the verticaltravel through which a discharger shoe. element must pass in scraping orscavenging the inner wall surfaces of the basket.

With the foregoing considerations and limitations in mind, we havedevised a special automatic discharger shoe apparatus which, in thepreferred embodiment shown in the drawings, is suitable for use with anysize basket within the range generally indicated above and withoutunduly interfering with the supporting frame work of the centrifugalseparator and without requiring any change in the conventional operationof the centrifuging process.

This special discharger shoe apparatus generally comprises a means formoving a discharger shoe element or blade from a position above andoutside of the basket and curb to a position of register directly abovethe openings in the curb and basket; also separate means for moving thedischarger shoe downwardly through the opening in the basket into aposition in which the blade or shoe occurs just below the upper flangededge of the basket; and also means for selectively lowering and raisingthe blade while in contact or in close proximity to the inner surface ofthe curb. Furthermore, the means for rotating the blade about a verticalaxis and for moving it into and out of the basket are capable of beingreversed in their direction of movement.

In order to provide for automatically lowering and raising thedischarger shoe while in the basket, we have found that it is importantto employ a control which can be operated independently, and we havedevised a special telescoping discharger shoe holder arrangement, theprincipal parts of which are included within the bracket A--A of Fig. 8.In accordance with the invention this shoe holder arrangement issupported in a suspended position above the curb so that it can be swungabout a vertical axis, and yet can be raised and lowered as a completeunit without utilizing the telescoping action until a desired point ofregister is arrived at.

Considering first the means for supporting this telescoping shoe holderarrangement in a position such that it can be rotated about a verticalaxis, we provide a supporting base structure which preferably is securedat the upper side of the curb 16 and which includes a base plate 22adapted to be bolted to the curb. Extending upwardly from the base plate22 is a reinforced hollow body section 24 which is formed at its upperend with a flat bearing surface 26, as better shown in Fig. 10. It iscontemplated that other types of supporting base structures may beemployed, for example one which might rest upon the floor and whichmight be movable toward and away from the centrifugal separator, atwill. However, the invention will be described with reference to thepermanently attached type of supporting base structure shown in thedrawings, it being understood that the invention is not limited to thisor any other particular form of base.

In the position of the supporting base structure shown in Fig. 7, itsinner or right-hand side will be seen to be formed with an enlargedbearing portion 28 which is chosen of a size such that it projectsinwardly over the inner edge of the curb 16, as is also shown in Figs. 2and 3. The bearing portion 28 comprises a cylindrical member with avertically extending bore formed therein. Received in this bore is atubular guide 30 which is rotatable in the bore and which is alsodesigned to slidably receive the telescoping shoe holder structureincluded in bracket AA, as noted above.

Resting upon the upper edges of the tubular guide and cylindricalbearing member 28 is a stop ring member 32, better shown in Fig. 9,which is formed with a keyway in which is received a key 34 for keyingthe stop ring to the tubular guide 30, as may be seen from an inspectionof Figs. 9 and 10.

The stop ring is constructed on one side with a lug 32a and on anopposite side with a second lug 32b through which lugs are adjustablythreaded respective stop elements 33 and 35. These stop elements areadapted to swing into engagement with a projecting part 37 formed on thebearing 28 and limit rotation of both the collar and guide about avertical axis, as more fully described herein.

The tubular guide 30 has its outer peripheral surface formed with a gearportion 36 (Fig. and arranged to mesh with the gear portion 36 is a rackmember 38 slidably supported in a second bearing member 40 formedhorizontally along the upper part of the body 24. The rack member 40 isattached at one end thereof to suitable means for reciprocating the racksuch, for example, as an air-operated cylinder and plunger unitgenerally denoted by the numeral 42 and shown at the right-hand side ofFig. 10 and also in Fig. 4.

As such an air-operated device is of well known character, no detaileddescription is thought to be required other thant to say that the rackis attached to a piston 42a which is reciprocally actuated by airadmitted to the cylindrical portion 42b through two spaced-apartconduits 42c and 42d. These conduits connect with an electricallyoperated air valve 43 of conventional construction such, for example asan air valve sold under the trade name Electroaire. A conduit 45 servesto conduct air to valve 43 from a master valve 64 which is, in turn,connected to a source of compressed air through a conduit or pipe 64a.

Mounted on the flat surface 26 of the body portion 24, and securelyattached thereto, as for example by fastenings such as bolts, is anupright member 44, best shown in Figs. 2 and 8. This upright member hasan enlarged top flange section 46 upon which is mounted a verticallymovable suspension unit from which hangs the telescoping shoe holderarrangement included in section A--A of Fig. 8.

Included in the suspension unit is a second air-operated cylinder andpiston unit 48 of the same general character already described,including a cylinder 50, a plunger or piston 52 contained therein andhaving a piston rod 54, as shown in Fig. 6. Two conduits for admittingair to the cylinder 50 at either side of the piston are indicated by thenumerals 56 and 58, respectively, and these conduits communicate with anelectrically operated air valve 68, in turn connected to the mastervalve 64 already described.

The piston rod or stem 54 shown in Fig. 6 supports at its upper end anarm 66 which extends outwardly and has secured to its outer end, at theunder side thereof, a threaded fitting 68 formed with two passageways 70and 72. Threaded into these passageways are respective conduit members74 and 76 which are connected to another air valve device 75 of theclass described above. The air valve 75, in turn, is connected by a tube77 to a master air valve 64. Also threaded into the bottom of thefitting 68 are two other tubular conduits 78 and 80 which com municatewith the passageways 72 and 70, respectively, as is better shown in Fig.8.

In accordance with the invention we mount the telescoping shoe holderstructure included within the bracket A-A of Fig. 8 upon the outertubular conduit 78, and at the same time we locate the lower part of thetelescopiug structure in the rotatable guide 30, as shown in Fig. 8. Bymeans of this arrangement it will be apparent that the entire suspensionunit and the telescoping holder structure may be readily raised orlowered together when the air cylinder 48 is operated. Likewise it willbe apparent that by slidably keying the telescoping holder structure inthe tubular guide 30, this vertical movement may be accomplished and, atthe same time, the telescoping holder may be rotated by the guide 30 andits rack 38 into different positions of adjustment which are describedin detail at a later point.

Considering now in greater detail the telescoping unit it will beobserved that at the lower end of the tubular conduit 78 and in threadedrelationship therewithin, there is provided a plug member 82 surroundingthe conduit 80 and secured by a locking unit 84 which is, in turn,threaded around the extremity of the conduit 80. Fixed on the outerperipheral surface of the conduit 78 adjacent to the plug 82 is a pistonor plunger member 86 carrying piston sealing rings 83. The pistonsupports in sliding relationship with its peripheral surface a sleevemember 90 which is closed at its upper end by a threaded cap 92 and agland nut 94. The piston 86, in its location shown in Fig. 8, occurs inan intermediate position relative to the ends of sleeve 90 and definesan upper chamber 96 and a lower chamber 98. Communicating with the upperchamber 96 is a passageway 100 which leads to the interior of theconduit 78 and, in turn, to the passageway 72 and its respective conduit76. Communicating with the chamber 98 is the open extremity of thetubular member 80 so that there is formed a continuous passageway fromchamber 98, through conduit 80, and thence through the passageway 70 andis respective conduit 74.

At the lower end of the sleeve 90 is internally threaded another plugmember 102 which is provided with two serrated sections 104 and 106normally held in locked relationship with respect to one another bymeans of adjustment nut 108, all as shown in Fig. 8. The lowermostsection 106 has solidly fixed to it a blade holder 112 which carries adischarger shoe element 114 of the well known blade type.

At its outer peripheral surface the sleeve 90 is formed with a verticalkeyway and, similarly, the tubular guide 39 is formed with acomplimentary keyway, in which keyways is located a key 93, as shown inFig. 8. This key member allows the tubular guide to turn the sleeve 90with it when rotated by the rack 38.

It will readily be seen that since the sleeve 90 is slidably mounted onthe outer conduit 78 and is also slidably keyed in the tubular guide 30,it is free to move either up or down. To produce movement of the sleeve,and its holder portions vertically, compressed air may be released intothe chamber 98 through the passageway 70 and thence out through theconduit 80; The pressure thus exerted causes the sleeve to slidedownwardly on the piston 86 to a desired point. Alternatively, to raisethe sleeve and its holder, compressed air is released into the chamber96. This may be done by opening the valve which controls flow ofcompressed air through the conduit 76 and into passageway 72 and thencethrough the conduit 70 and out of the ports 100. Pressure will then beexerted in the chamber 96 and this will cause the sleeve to moveupwardly relatively to the piston 86. By selecting a sleeve length ofthe proper magnitude it will be readily understood that we may providefor a length ofstroke which will be adequate to move the discharger shoe114 all the way up and down the inner peripheral surface of the basket20.

In the operation of our discharger shoe'the telescoping sleeve and shoeholder structure will normally be located in a raised starting position,as shown in Fig. 2. In this position the discharger shoe has been movedinto a location above the curb and basket, as shown, and moreover theshoe has been rotated about a vertical axis into a position, forexample, in which the blade occurs immediately above the top side of thecurb, as suggested in Fig; 2.

Assuming now that a centrifuging operation is nearing a point ofcompletion and it is desired to apply the discharger shoe to the innerperipheral surface of the basket 20, the master valve 64' may be openedand this is followed by a series of timed movements in the selectorvalves 43, 60 and 75. Ordinarily the first movement is to producerotation of the tubular guide and telescoping sleeve about a verticalaxis. This is accomplished by means of the member 43 which, when opened,produces a transverse movement of the piston 42a and, with. it, the rack38 which acts through the segmental gear portion on the tubular guide tomove thedischarger shoe inwardly above the openingin the curb.

In Fig. 7 We have illustrated fragmentarily portions of the stop ringmechanism and the discharger shoe. shown in one typical position withthe stop element 33 located against the projection 37. The inward.rotation of the tubular guide and telescoping holder operates to swingthe member 114 into the broken line. position shown at the right-handside of Fig. 7, and it is pointed out that this inward rotation of thedischarger shoe is controlled and limited by the adjustable stop.element 35 which, at one point, comes into engagement with theprojection 37 to prevent further rotation.

With the discharger shoe in the broken line position shown in Fig. 7,the member 60 is next opened to deliver compressed air into the cylinder50 of the vertically movable suspension unit. The pressure of thiscompressed air delivered through the conduit 56 causes the piston 52 todescend and carry with it the extension arm 66 and the telescoping unitthroughout a short path of travel. In one satisfactory type of operationit has been found that a travel of approximately seven inches by thissuspension unit will produce a suflicient change in position of thedischarger shoe to locate it just below the flanged edge of the basket20, as noted in Fig. 3.

In order to move the discharger shoe into engagement with, or into closeproximity with respect to, the inner peripheral surface of the basket,it will be understood that the rack member, through the valve mechanismalready described, has to be reversed to rotate the tubular holder andshoe in an outward direction. This is done by conventional switch meansin the Electroaire valve 4-2. Thereafter compressed air is admittedthrough conduits 70 and 78 to the chamber 98 by means of the valve 75,operating in the manner already described, to cause the sleeve member todescend and carry with it the discharger shoe member throughout thelength of the basket wall into a position, for example, such as thatshown in dotted lines in Fig. 3. The precise arrangement of theextremity of the discharger shoe may vary, depending upon the thicknessand consistency of the material which may be coated or caked around theinside of the sep arator and which is required to be removed. In someinstances, for example, it may be preferable to adjust the end of thedischarger shoe so that it does not actually engage the basket peripherybut merely presses firmly against the cake as the basket rotates aroundits axis. This action gradually scrapes or removes caked material. Inother cases where a very soft body is adhering to the basket wall, theshoe may be rotated all the way inwardly to the point where itimmediately begins to contact por tions of the basket periphery.

As soon as a proper scraping or scavenging action has been achievedwithin the basket, the discharger shoe may beeither raised into theposition which it occupies in Fig.- 3, or it may be first swung awayfrom the basket wall and then raised into a position above the curb andbasket, and finally rotated out to the starting position noted above.-

To' cause the discharger shoe to rise into its full line position ofFig. 3 the telescoping holder structure is operated by reversing theaction of valve 75 and causing air to flow into the conduit 72 whichescapes through the ports 100' and causes the sleeve member 90 to rise.in the same manner the rack may be actuated by reversing its controlvalve to swing the discharger shoe inwardly away from the basket andcurb edges, and thereupon the suspension unit is operated by the valve60 to raise the piston 52 and piston rod 54 with the arm 66. Thereafterthe rack is again operated toswing the shoe out to its startingposition.

We may also desire to employ the mechanism described with various othertypes of discharger shoe elements. Thus, in Fig. 5' we have shown adischarger shoe element which is solidly secured to a telescopingholder-struc ture rotatable in a tubular guide 122. The discharger shoein this arrangement extends inwardly and angularly against the path ofrotation of the basket 124, as has been suggested in dotted lines inFig. 5. Thus the shoe opposes the rotation of the basket, and the forceof the haskettends to cause the shoe to be forced outwardly against thewall of the basket by the leverage applied". This type of dischargershoe element may be preferable for certain types of hard caked materialwhich is not readily displaced from the basket periphery.

It should be understood that various other modifica tions and changesmay be resorted to. For example, we may provide suitable relay control,means for operating; the selector valves 43, 60 and 75 in a differentsequence or in a fully automatic sequence, so that by merely closing onecontrol switch all of the other switches will be operated in apredetermined sequence in accordance with well known relay timingdevices of this general class. Similarly, we may vary the actuatingmeans employed. For example, in place of air cylinders and reciprocatingplungers or pistons, we may employ an hydraulic type of control Where afluid, such as a liquid under pressure, is utilized to comprise theactuating force. Various other electrical arrangements also may beutilized, if desired.

From the foregoing description of our invention it will be evident thatwe have provided a rugged, dependable,

"7 and eflicient discharger shoe control mechanism in which we have madeprovision for a positive stop to cause the discharger shoe to enter, onits down stroke, very accurately under the basket cap or flange. It ispointed out that it is very important that this particular step becarried out in such a way that no chance of error or failure ofoperation can arise. By employing the cylinder 50 and the plunger 52,the seating of the plunger in its cylinder constitutes a positivemechanical control when, when once set, will permanently remain ineffect to always ensure the correct location of the discharger shoeblade at the time it is swung outwardly against the basket wall.Obviously the same accurately and permanent stop arrangement is presenton the upstroke when the piston 52 seats against the top of the cylindermember 50.

It is also pointed out that a second point of unusual strength andrigidity in the construction of the working parts is derived from thenovel telescoping holder arrangement wherein the scraper blade, insteadof being supported at the end of a piston stem or shaft, is supported bymeans of a cylindrical sleeve of relatively large diameter which tendsto develop relatively greater rigidity and strength than could beobtained with any reciprocating plunger or piston construction.

Moreover, the mechanism described is particularly suited to meeting withsafety requirements. For example, the controls may be arranged so as toleave pressure on the cylinder 42 at the end of the rotary cycle so thatthe discharger shoe element will always be locked in a safety positionabove the first curb top. In the event of air or fluid pressure failurethis discharger shoe element cannot accidentally move into a position ofinterference. It is further contemplated that the controls may beelectrically connected with the actuating means for rotating thecentrifugal separator and also with various well known mechanisms forapplying a braking action to the separator when in motion.

While We have shown a preferred embodiment of our invention, therefore,it will be understood that said invention is limited only within thescope of the claims as appended hereto.

Having thus described our invention, what we desire to claim as new is:

1. A discharger shoe mechanism for a centrifugal separator of the classhaving a rotary basket and a curb in which the basket is enclosed, saiddischarger shoe mecha position in which the shoe element may be loweredinto the said basket and then rotated into engagement with the basket,and means for lowering and raising the shoe element and bolder whilewithin the said basket, the said means for rotating the shoe and holderincluding a base member mounted on the curb, said base presenting abearing portion, a tubular guide rotatably received in the bearingportion, a sleeve member forming a part of the holder means and beingoperatively connected to the tubular guide, and gear means locatedthrough the bearing portion for rotating the tubular guide.

2. A structure as defined in claim 1, including means for producingreciprocating movement of the sleeve member in a vertical direction.

3. A structure as defined in claim 1, in which the vertically disposedholder means comprises a telescoping sleeve, a hollow shaft having thesleeve telescopically mounted thereon, a piston carried on the shaft andadapted to slidably receive the telescoping sleeve, said shaft beingformed with fluid conduits which communicate with spaces occurringwithin the telescoping sleeve at either sideof the piston.

4. A discharger shoe control mechanism for a centrifugal separator ofthe class having a rotary basket and a curb in which the basket isenclosed, said discharger shoe control mechanism including a dischargershoe element presenting a scraper blade, a vertically disposed holderfor supporting the shoe element in suspended relationship above the saidcurb, said holder comprising an outer tubular member having the saidshoe element attached at the lower end thereof, hollow shaft means forslidably supporting said tubular member, fluid pressure responsive meansfor moving the said tubular member relative to its hollow shaft, meansfor raising and lowering the tubular member and its supporting parts asa unit, and means for rotating the tubular member and shoe element abouta vertical axis in any position of vertical adjustment.

5. A discharger shoe mechanism for a centrifugal separator of the classhaving a rotary basket and a curb in which the basket is enclosed, saiddischarger shoe mechanism including a discharger shoe supportingstructure having a base adapted to be secured at the upper side of thecurb, said base presenting a bearing portion formed with a vertical boretherein, a tubular guide member received through the bore of the bearingportion and rotatable therein, said tubular guide presenting at itsouter periphery a gear portion, said base further including a secondbearing portion formed with a transversely disposed bore, a rack memberslidably received through the transversely disposed bore in a positionto engage with the gear of the tubular guide, means for reciprocatingsaid rack, a discharger shoe holder unit including a sleeve memberslidably keyed in said tubular guide, a discharger shoe element rigidlysecured at the bottom of the sleeve member, a piston received in thesleeve, fluid pressure means for raising and lowering the dischargershoe holder unit, and fluid pressure means for reciprocating the sleeverelative to the said piston.

6. A structure as defined in claim 5, including a stop ring supportedabove the said first bearing portion in keyed relationship with thetubular guide, and a stationary stop piece arranged on the said firstbearing portion in position to limit rotary travel of the said stopring.

References Cited in the file of this patent UNITED STATES PATENTS1,202,936 White Oct. 31, 1916 1,620,568 Ordway Mar. 8, 1927 1,965,840Jones July 10, 1934 1,968,491 Jones July 31, 1934 2,063,472 Tholl Dec.8, 1936 2,234,332 Brewer Mar. 11, 1941 2,467,023 Foster et al Apr. 12,1949 2,628,719 Hertrich Feb. 17, 1953

